Studies on the time course of the effects of the probiotic yeast Saccharomyces boulardii on electrolyte transport in pig jejunum.

Orally administered Saccharomyces boulardii (synonym Saccharomyces cerevisiae Hansen CBS 5926) has already been shown to affect relevant functions of the mucosa in pig jejunum such as lowering the secretory response to theophylline or stimulating sodium/glucose cotransport, but knowledge of time-dependent relationship is minimal. In this study we examined the effects of S. boulardii on sodium (Na+) and chloride (Cl-) transport in pig jejunum under nonstimulated (basal) and stimulated (secretory) conditions. For this purpose the conventional Ussing chamber method was used for measuring electrical parameters (short circuit currents, Isc; tissue conductances, G(T)) and electrolyte transport of isolated intact jejunal epithelia in the absence and presence of the secretagogue theophylline (10 mM, serosal side). Time profiles of the mucosa response were assessed by treating animals perorally with S. boulardii for 0 (control), 3, 8, and 16 days. Intestinal tissues were obtained from growing pigs in the weight range between 25 and 40 kg. All animals were fed twice daily and received 1.0-1.6 kg/day of a standard diet avoiding probiotics as food additives. After a 9- to 10-day adaptation period the diets for treated animals were supplemented with approximately 1.8 x 10(7) colony forming units (CFU)/g feed of the probiotic. Whereas basal tissue conductances were not affected by treatment duration, basal Isc values decreased significantly during 8 days of treatment, by 26%, indicating a lower electrogenic net ion transport, which, however, was reconstituted after 16 days. This effect could be explained by almost the same reduction of basal Jms of Na+ during 8 days of treatment, whereas respective flux rates in the opposite direction remained stable. Under basal conditions unidirectional and net flux rates of Cl- were not affected by S. boulardii. Induction of secretory conditions by theophylline revealed pronounced increases in net Cl- secretion but this effect was more than 60% lower after 8-day S. boulardii application, and this was reflected by a respectively lower Isc stimulation. Interestingly, this inhibitory effect on the secretory response could no longer be observed in the 16-day group. And this was reflected by a respectively lower Isc stimulation. A similar effect could be observed regarding net Na+ flux rates. Residual fluxes were affected neither by S. boulardii nor by theophylline, therefore, Isc values can be explained completely by respective Na+ and Cl- fluxes. In conclusion, S. boulardii has specific duration-dependent effects on the secretory response of the pig jejunal mucosa which developed during 8-day treatment but disappeared during further application. Thus, this study supports the concept that probiotics may exert beneficial effects in the gastrointestinal tract.

T lymphocyte subpopulations in leprosy patients and their relation with circulating immune complexes.

The possible relationship between circulating immune complexes (CIC) and peripheral T lymphocyte populations was studied in thirteen active multibacillary leprosy (10 lepromatous--LL--and 3 borderline lepromatous--BL--) and 19 matched controls. Theophylline-resistant T cells (The-R, a lymphocyte subpopulation displaying helper activity on B cells) and total T cells were assessed by means of the E rosette technique, with and without previous theophylline incubation, 1h 37 degrees C, respectively. CIC were quantified by 125I-C1q binding test. Although leprosy patients showed a statistical non significant light depression in total T cells the remarkable variability in circulating levels of The-R T cells enabled us to separate them into two well delineated groups (in relation to this variable p less than 0.001) with no difference in age, sex and bacteriologic state: a) leprosy patients with The-R T cells proportionally conserved (6LL and 2BL); b) leprosy patients with The-R T cells proportionally depressed (4LL and 1BL). Patients belonging to the latter group showed the highest statistically significant levels of CIC. Even though we do not discard an unknown factor being responsible for our findings, we believe that this inverse relationship between elevated CIC and depressed The-R circulating T cells might be representing a lower helper activity on antibody synthesis intending to reduce its excessive production.